Problem: Simplify the following expression: $n = \dfrac{1}{10x} + \dfrac{1}{5x}$
Answer: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $10x$ and $5x$ $\lcm(10x, 5x) = 10x$ $ n = \dfrac{1}{1} \cdot \dfrac{1}{10x} + \dfrac{2}{2} \cdot \dfrac{1}{5x} $ $n = \dfrac{1}{10x} + \dfrac{2}{10x}$ $n = \dfrac{1 +2}{10x}$ $n = \dfrac{3}{10x}$